494 MURICID. 
operculum with a still narrower aperture. The branchize are 
semilunar, one large, one smaller, of a dark brown colour; 
immediately above the larger one are the coarse pale yellow 
mucous filaments, which are edged with a dark border. The 
ergane générateur male is a very long, narrow, strap-shaped 
appendage, poimted at the end, sprmging under the right ten- 
taculum, and lymg doubled up and reflected back in the 
branchial cavity. The ovarium and liver occupy all the 
posterior volutions, and run mixed together to near the 
pylorus ; the two organs are easily distinguished, the ovarium 
being pale yellow, and the liver red-brown. In the male the 
testis replaces the ovarium. I have a little exceeded the limits 
of ordinary description on account of this animal beg the 
type of the section. 
This elegant species is sufficiently abundant in the coralline 
zone at Exmouth. 
M. GInannIANUvs, nobis. 
Pleurotoma Ginannianum, Philippi, Moll. Sicil. 
Mangelia nebula, Brit. Moll. ii. p. 476, pl. 114. f.7, 8,9; (animal) 
pl. R.R. f.7. 
Animal spiral; ground-colour white or pale yellow. Mantle 
plain, even, except the branchial fold, which, when the animal 
is in motion, floats freely beyond the canal, and from its con- 
stant movement appears to act as a fecler; the mantle also at the 
upper part of the outer lip lines a very inconspicuous emargi- 
nation of the shell, forming a minute anal conduit. The head 
is small, white, compressed, and does not at all imterfere with 
the basal conjunction of the tentacula ; the proboscidal fissure, 
as in Murex undatus, is below the coalescing membrane ; the 
tentacula are short, flake-white, with eyes at the terminal 
surface of external offsets nearly extending to their points. 
The foot, when fully extended, reaches to the third or fourth 
posterior volution; it is pale yellow below, with marginal 
transverse white markings, and sprinkled on the upper surface 
with intense flake-white spots ; it is subrotund in front, scarcely 
auricled, narrow, gradually tapering to a blunt, slightly emar- 
ginate point. There is no operculum, and in this respect and 
in all the other organs it agrees with Murex gracilis. This 
